The acute withdrawal of alcohol from patients with histories of chronic dependence is known to precipitate a syndrome that is variable in its presentation. The central nervous system correlates of alcohol withdrawal have been studied previously. However, most studies have focused on >35 year old patients with limited or unspecified histories of other drug abuse. We therefore have little understanding of the CNS effects that result from combining alcohol withdrawal with other drug withdrawal, or with medical (malnutrition) or psychiatric (antisocial personality) variables that frequently accompany other drug abuse. Such knowledge is particularly relevant in the context of the movement toward outpatient detoxification and unanswered questions regarding the abilities of such patients to safely perform tasks at home or at work while simultaneously undergoing alcohol/drug withdrawal. In this study, we propose to compare the neurophysiological and neuropsychological status of 150 alcohol dependent patients with (n=75) or without (n=75) co-morbid cocaine dependence. A group of non drug-dependent subjects (n=35) will be tested as a control. The assessment battery will include measures of resting EEG activity, sensory functioning, motor functioning, visual and auditory selective attention, and short term memory. The additive and/or interactive effects of vitamin deficiency and antisocial personality disorder will also be evaluated. The principal hypothesis states that patients concurrently withdrawing from both alcohol and cocaine dependence will be characterized by impaired performance on specific measures of EEG activity, and motor and sensory function.